I would definitely agree that such questions be closed — I have even suggested exactly the same course of action for a similar class of questions — but that's less because I feel that closing is the optimal course of action and more because downvoting alone is not doing the job.
What is most important is that these questions be downvoted. Even if they stay open, a downvoted question will be removed from the front page (without necessarily forbidding them from being answered), allowing upvoted questions to take the fore where they belong.
The mouseover text for the downvote button is as follows:
This question does not show any research effort; it is unclear or not useful
- For the most part, too-basic questions do not show any research effort. There might've been research effort, but if they don't show it we really don't have any basis to know what they already know, or are expected to know. Do they even know the basics of Islam? Do they need a crash course in Hadith Sciences 101? Do they even know about the different schools of fiqh, and which one they want an answer from? Should the answer assume they know everything about everything except for the exact question they asked? Who knows.
- Too-basic questions are often also unclear, not so much in the sense of it's not a simple question, but it's unclear what they're looking for in an answer. Is it really as basic as it looks? Is it in fact a controversial topic that's going to end up requiring an essay to answer? Is the questioner actually only interested in one particular aspect that they failed to mention, and most of the answer is just going to end up irrelevant? Who knows.
- Thirdly, too-basic questions are generally not useful. We are not trying to replace Google, or Wikipedia, or Islam-QA, or any number of other well-established resources; questions that just ask us to duplicate (and often with lower quality) what can already be found there have no actual value to the site, nor to the experts we're trying to attract.
Many problematic questions which only meet one of these criteria could still well deserve to be downvoted. Questions which meet all three criteria should be downvoted, downvoted hard, and downvoted with extreme prejudice. If it was possible to downvote multiple times, I would totally recommend you do that too.
Otherwise, such questions will not only clutter up the front page and prevent actually interesting questions from getting viewed, but they will actively drive away the experts we need to actually answer those interesting questions. Downvoting on questions is free for exactly that reason.
This class of questions undoubtedly needs to be removed from the front page. If downvoting doesn't do the trick, as it was designed to do, then stronger courses of action are necessary. This would include closing (in most cases, "Unclear what you're asking" as per point two above would probably suffice) or even just having them flagged for outright deletion, but I feel that such drastic measures should only be temporary until voting activity is actually sufficient to remove them naturally.